78 MISC. PUBLICATION 7 02, U. S. DEPT. OF AGRICULTURE 



dry. Pastures dry up and furnish very little feed until late in Sep- 

 tember. According to farmer experience and experimental results, 

 summer irrigation of pastures increases production of forage from 25 

 to 50 percent during the dry period (22) . Many farmers use sprin- 

 kler irrigation to increase forage production. At present prices, costs 

 of equipping and installing the more common designs of sprinkler 

 irrigation systems vary from $40 to $100 per acre. The economic 

 feasibility of such installations must be determined for each indi- 

 vidual farm. In general, sprinkler irrigation is adapted to shallow 

 soils which do not hold water well, and to areas in which the topogra- 

 phy is such that leveling the land is too expensive and the supply of 

 water for border irrigation is limited. Sprinkler irrigation re- 

 quires considerably less water than does the open-ditch method. 



IN THE SOUTHWEST 



Development of suitable grasses with limited water requirements 

 will have to precede any substantial expansion of irrigated pastures 

 in the Southwest. One of the chief difficulties connected with pastures 

 in the irrigated valleys and scattered pump-irrigation areas of New 

 Mexico and Arizona is the lack of sufficient water. In the irrigated 

 areas of the southern portion of these States at present, irrigation 

 farming is devoted primarily to production of cash crops, cotton and 

 alfalfa, and some specialty crops. Alfalfa is often included in crop 

 rotations mainly to improve soil structure and fertility and to increase, 

 cotton yields. Despite relatively high-water requirements, alfalfa 

 is often used for pasturing and feeding cattle and sheep. The Ari- 

 zona Agricultural Experiment Station is conducting research on the 

 development of grass and grass mixtures that will do well on the lim- 

 ited amount of water available to farmers in the State. Cotton will 

 produce good crops on about 3 acre-feet of water, but pastures re- 

 quire at least 5 to 6 acre-feet. 



The increasing demand on West coast markets for more and better 

 quality beef has increased the returns from finishing of cattle on west- 

 ern irrigated pasture. An example is a year-round beef-finishing 

 irrigated ranch located in a mountain valley of southern Arizona. 

 The present operator bought this 700-acre unit in 1946. At that time 

 it included 70 acres of cropland, of which 20 were irrigated. The re- 

 mainder was very poor mesquite range of little or no value for graz- 

 ing. Approximately 225 acres of this mesquite land has been cleared, 

 grubbed, and leveled at an estimated cost based on today's prices of 

 $65 per acre. Water for irrigation is supplied by three wells which, 

 equipped, cost from $1,200 to $1,500 each. 



The 70 acres of former cropland, in addition to the newly improved 

 land, have been seeded at the rate of 22 pounds per acre with a pasture 

 mixture known as Arizona No. 1 which is composed of the following 

 grasses : Perennial ryegrass, 3 pounds ; Alta fescue, 5 pounds ; orchard 

 grass, 4 pounds; Dallis grass, 6 pounds; alfalfa (Southwest type), 

 2 pounds; annual sweetclover (Emerald), 1 pound; and bur-clover, 

 1 pound. 



Six hundred yearlings weighing around 450 pounds are bought each 

 year from ranchers in Arizona and New Mexico and, after finishing 



